HO STATES OF INSECTS. 



only six legs : namely, an anal pair, and two ventral ones, 

 situated on the eighth and ninth segments. 



4. The larvae of the Geometers (Geomctrcc F.) have 

 butyb^- prolegs ; of which two are anal, and two spring 

 from the ninth segment. It should be observed, how- 

 ever, that the larvae of Hemigeometers, and even of some 

 of those that have ten prolegs, where the four anterior ones 

 are much shorter than the rest, move in the same way as 

 the Geometers. This even prevails in a few where these 

 organs are all of equal length. 



5. Many of the larvae of Tinea L. which live in the in- 

 terior of fruits, seeds, &c, have but one pair of prolegs, 

 which are attached to the anal segment. 



6. The larvae of Haworth's genus Apoda (Hepialus 

 Testudo and Asellus F.), remarkable for their slug-like 

 shape and appearance, move by the aid of two lateral 

 longitudinal pustule-like protuberances, which leave a 

 trace of a gummy slime in their course. 



Hymenoptera. — The larvae of the different tribes of 

 Tenthredo L., almost the only Hymenopterous insects in 

 which prolegs are present, have a variable number of these 

 organs ; some sixteen, as the saw-fly of the willow ( T. lu- 

 tea L.), and this is the most numerous tribe of them, in- 

 cluding the modern genera, Cimbex F., Pterophdrus, &c. 

 Others have fourteen, as that of the cherry ( T. cerasi L.); 

 and many others with only nine joints to their antennae. 

 A third class have only twelve, as that of the rose ( T. Ro- 

 sce L.), but this contains but few species. The last class 

 contains those that have no prolegs at all, but only the six 

 horny ones appended to the trunk. Of this tribe, the 

 caterpillars of which have a very different aspect from 

 the preceding, are those of the genus Lyda F, ( 11 cry- 



